Fan Clutch Problems (I think?)

[jrm5f2]

Good Morning Everyone,

I have a question, how does one know if the Fan clutch is failing? The reason for this question is that I noticed that my a/c takes a long time to cool the cabin and only cools the cabin if I am driving at about 60mph and above. I have checked my a/c pressures and they all seem to be within tolerance of what the service manuel says it needs to be. I thought at first there could be so sort of restriction in the line, but I noticed that when I crank the vehicle up the fan does not blow loud as it once did.

Mind you that is when the A/C was working normally. When searching the internet I learned that the cooling fan plays a significant role by moving air through the a/c condenser to help cool the freon. Again my truck has always made a loud fan noise on the first startup and while driving on hot days, but now I don't hear that anymore. When I spin the fan with my hand the fan does spin some but I also still feel some resistance. When I looked at some youtube videos it looked like if the fan was any good it should not be able to spin at all freely. I just wanted to know if anyone has any thoughts on this or if I am looking in the right direction. There no CEL, service engine light illuminated and no stored codes. Just for fun can one of you guys check your fan clutch for me.

Thanks (2011 Infiniti QX56)

 

[marctronixx]

the big clutch fan can spin freely with a little resistance.. i mean LITTLEEEEEEE... its a clutch after all so when the system needs for more air to be sucked in through the condenser, the fan will be engaged by the clutch.

you should NOT hear the clutch fan power on every startup! it will on occasion but its not a typical thing that occurs.

how do you know your refrigerant is properly charged? are you licensed in R134a recovery and installation? do you have the proper equipment to measure? or did you go to a mechanic and have them diagnose it? did you run the system on MAX cool high fan speed at engine temp?

id say your refrigerant is low, over the fan not working.

itr could also be an electrical issue that may be preventing the fan from engaging, but that cant be diagnosed over the internet.

 

[jrm5f2]

Thank you for your response.

Are you saying that the fan should spin Freely, because I can only spin it to at least a half turn. Base on Youtube videos I was assuming I should not be able to spin my fan freely to a half turn? It should be able to be turn, but not just spin or am I wrong?

Also, the reason why I don't think it is the a/c is that I just replaced the a/c compressor and recharge the system based on the service manual specs, yes using the proper equipment and technique (did not use the can with the little gauge on it ...lol).

After replacement, it worked perfectly up until now. I again checked the pressures for Low and High side and the pressures look to be in spec. Funny, when all this started to happen that is when I noticed the fan speed difference. Like I said I use to hear the fan for a second or two when I crank up the vehicle and I used to always hear the fan sometimes at low speeds, especially on a hot day.

I don't anymore. I know our trucks use an electric engaged clutch, so I am wondering how often these things go bad, if at all?

 

[marctronixx]

The huge truck fan with the electronic clutch should spin freely when the engine is off. I mean you wil fee resistance but you can rotate it and rotate it and rotate it. It won’t spin forever like a roulette wheel but if you use your finger to push one of the fan blades it will turn round and round with your finger.

Its possible the fan clutch could be faulty. Sounds like you have the service manual and if you do you can check out the troubleshooting steps related to it.

When the car is running, do you see the clutch fan rotating ever so slightly or is it just froze and not moving?

Yea time to time i hear the clutch fan ROOOAAARRRRRRRR on first startup in the morning or if the engine has sat our in the sun and has heated up the engine room, but i DONT hear it often—its rare (i actually LOVE the sound,sounds like a mac truck )

Yea you are correct it turns on when user a heavy AC load, engine getting hot, etc. and based on your experience if you would hear it more often (all of our driving habits, weather in our respective locations , will play a part on how often we hear the fan)and now you are not, it could be the clutch fan. Does your engine temp shoot up when this happens? Have you noticed the engine temps increase since the fan started not acting right?

And for record, where are you located? How long have you had the car? Curious why the compressor was replaced?

Have you tested the system for leaks? Running dye in the system to see if anything is leaking?

If you have a video you want to share for reference showing how your fan is behaving,that may be helful. I could also do the same thing and show you how mine behaves. Ive a 2012 qx all options.

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[jrm5f2]

I hear you, love the sound! I know a lot of people don't but man it does roar to life...lol.

To answer your question I live in North Florida where we have had some pretty hot days say the least. The truck is 2011 and purchased two and a half maybe three years ago. The temperature gauge does not show an increase in temperature. The fan is moving when the truck is on, but when the truck is off I can move it with my finger and spin it to about a half turn without holding it. I replaced my a/c because the clutch pulley broke and almost basically fried my unit. The internals of the a/c was fine, but because the way the clutch pulley gave up the ghost it was best to replace the whole compressor. I did the job myself per the service manual and everything worked, I did do a leak test and found that there were no leaks. I filled it with freon and a week after that checked the pressures to make sure everything was ok, it was.

Now here is where it gets funny, recently I did not drive my car for about a week and when I went to start it is when I noticed the fan did not make the roaring sound like it normally does. Keep in mind it is a Saturday morning in Florida temp was about 85 already. The a/c was turned on full blast when the truck was started. I let the truck sit for a minute before me and the family loaded up and it was still warm air coming out of the vents. Now as I was driving is when it started to cool a bit going about 60mph, but when we stop you could feel it get a little warm again.
I started to notice the truck was not making the fan noise it has always made at low speeds on a hot day or pulling off from a stop light. Again, just a week ago I was able to sit in my truck with the a/c on and cold air coming out with the truck not moving.

That is a little back story of why I suspecting the fan clutch, but here is what's funny yesterday while still trying to diagnose this thing, I ran across a TSB for this ITB-12-025 2011-2012 QX56; ENGINE FAN IS NOISY AND VEHICLE HAS POOR ACCELERATION. I look it over and decided to give the steps a try. I know this is to diagnose the fan noise, but it had the steps I needed to try to see if the fan works as intended. The first time I started the truck to let run with the a/c at max the fan speed stayed the same with no noticeable increase in speed and yes the vent was blowing out warm. I turn it off and fetched my daughter to help. I had her sit in the truck turn it on and rev the engine to 2500-3000 rpm per the instructions for about a min. After that, you heard the fan speed increase for about 30 seconds and drop back down. I had here do it for about three times and each time it did the same thing. What I observed was the a/c getting a little cooler each time we did that and the truck trying to increase the fan speed, it would, but only a little, but not to where it is completely noticeable from the cabin. My conclusion is that the fan is on its way out, but not completely. It is giving enough cooling so the truck does not overheat, but not enough for the a/c.

Today I plan on checking the pressures of the a/c to be completely sure and I will try to post them on here for review along with a video if time permits today.

 

[marctronixx]

Thank you for the detailed explanation. Being in Florida with the humidity can wreak havoc on the best of HVAC systems, so i hear you!

Does your car sit out in the elements normally or is it in a garage?

Yeah when the car is off and you spin the fan with your finger, it wont spin freely as if it were in a vacuum. It will stio spinning shortly after your finger stops pushing it. This is normal.

Is your high pressure side sweating when hvac is on max cool?

I don’t think there is a need for a video because I was only wondering how the fan spun when the engine was on, and you stated it spins a little, and when the car is off you can freely spin the fan with your finger and it spins just a short itime after your finger releases.

Perhaps its simply the clutch fan—here’s a video that may be helpful to the conversation...

https://youtu.be/BR-uLMTaOXY

Here’s a fan test video. Don’t use your hand but use a magazine and if it spins freely backwards, its bad..

https://youtu.be/cOXcrbQRDWU

 

[jrm5f2]

Does your car sit out in the elements normally or is it in a garage?
Sometimes, usually it stays in the garage, but for the week in question it was outside.

Is your high pressure side sweating when hvac is on max cool? (low pressure) No but I found out why last night after getting a new set of a/c gauges(because my other one is messed up) and checking pressures again. I found a leak at the compressor on the side, this is what I get for ordering a compressor off ebay. I guess I will be doing this job again. I threw a half can of freon in there just to make sure, re-checked the pressures and wouldn't you know it started acting right...lol. After doing that I notice the fan speed started to change back to what it had been doing before this problem occurred.

So yeah, I was wrong about this one.

Although I found the leak I am still going to end up replacing the fan clutch for good measure after looking at the videos you shared, it seems like mine might be worn out a little.

 

[marctronixx]

hey bro, im happy you were able to diagnose the issue and hopefully this will fix everything. That’s what forums are for—to help. I’m no mechanic at all but I know how to research..

By the by, I do have a HVAC license for application and recovery of refrigerant. I was wise and got this back when they started tp phase out R-12. I took the ASE class in 1993 or thereabouts, passed, got my license and made some money the following year when little cans of R-12 went form a few cents a can to 25 dollars a can!

Anyway, happy to hear this—please follow up on the fan clutch and if replacing it was a good remedy.

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